The following relates generally to wireless communication and more specifically to low latency point to multipoint (PTM) communication.
Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems. A wireless multiple-access communications system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE).
Wireless multiple-access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example telecommunication standard is Long Term Evolution (LTE). LTE is designed to improve spectral efficiency, lower costs, improve services, make use of new spectrum, and better integrate with other open standards. LTE may use OFDMA on the downlink (DL), single-carrier frequency division multiple access (SC-FDMA) on the uplink (UL), and multiple-input multiple-output (MIMO) antenna technology. In some deployments, a base station may transmit unicast transmissions that are intended for reception by a single UE, and also may transmit broadcast or multicast transmissions that are intended for reception by two or more UEs. Broadcast or multicast transmissions may also be referred to as point-to-multipoint (PTM) transmissions.
In some cases, a wireless device may be configured for low latency communications. That is, the device may communicate with using a transmission time interval (TTI) that is shorter in duration relative to other TTIs in the system, which may reduce the time between transmissions. In some situations, data rates between a base station and a UE may be constrained based on a latency of transmissions. In some cases, such as if a quality of service of the related data traffic of the transmissions is high, it may be desirable to have higher data rates for certain traffic relative to other data traffic. Additionally, in some examples base stations and UEs may communicate using contention-based techniques on a shared radio frequency spectrum band, and transmissions with shorter duration TTIs transmitted to multiple UEs may enhance operations of such systems.